Girl Russian agreed to call, pouring heart out (6)
I believe the answer is:
daphne
'girl' is the definition.
I don't understand the remainder of the clue.
(Other definitions for daphne that I've seen before include "Shewd, sharp" , "nymph can be seen" , "Greek nymph and ornamental shrub" , "Bay" , "Small shrub, fem. name" .)